This invention relates to a regulated drawing unit for fiber material, such as a plurality of simultaneously advanced slivers (hereafter "sliver bundle") and is of the type which has at least one drawing field, a controllable and/or regulatable driving system for determining the extent of draft in the respective drawing field, a programmable control for the driving system and at least one sensor for determining the running fiber mass per length unit at a measuring location. Further, a draft-determining signal is stored over a predetermined period in a memory, and information is obtained from the stored values for adjusting the drawing unit.
In a known regulated drawing unit information is gathered for adjusting the drawing unit and/or for judging the quality of the master sliver bundles. Such information includes, for example, the CV value, the spectrogram and/or the length variation curve of the inputted sliver material. The draft-determining signal may be an output signal of a sensor or a setting signal for the drive system. It is a disadvantage of such conventional arrangements that the adaptation of the drawing unit to the regulation of the main drawing process, that is, to an rpm-regulation of the drive motors for the rolls of the drawing unit can be effected only in a limited manner. It is a further drawback that the information may be gleaned only from data concerning the inputted sliver material. Further, obtaining information is complex and also, the adaptation may be provided only for a certain processed assortment.